146746-36-3Relevant academic research and scientific papers
General Chemoselective Suzuki-Miyaura Coupling of Polyhalogenated Aryl Triflates Enabled by an Alkyl-Heteroaryl-Based Phosphine Ligand
So, Chau Ming,Yuen, On Ying,Ng, Shan Shan,Chen, Zicong
, p. 7820 - 7827 (2021/07/01)
This study describes a general chemoselective Suzuki-Miyaura coupling of polyhalogenated aryl triflates with the reactivity order of C-Cl > C-OTf using a Pd/L33 catalyst. The methine hydrogen and the steric hindrance offered by the alkyl bottom ring of L33 were found to be key factors in reactivity and chemoselectivity. With the Pd/ L33 catalyst, a wide range of polyhalogenated (hetero)aryl triflates, which were independent of the substrates and of the relative positioning of the competing reaction sites, coupled well with (hetero)aryl, alkenyl, and alkylboronic acids to obtain the corresponding products with good chemoselectivity and yields. The chemoselective reaction could easily be scaled up to the gram scale, and the use of parts per million levels of Pd catalyst (as low as 10 ppm Pd) was achieved.
Synthesis of Polybenzoacenes: Annulative Dimerization of Phenylene Triflate by Twofold C?H Activation
Uryu, Mizuho,Hiraga, Taito,Koga, Yoshito,Saito, Yutaro,Murakami, Kei,Itami, Kenichiro
, p. 6551 - 6554 (2020/04/10)
Polycyclic aromatic hydrocarbons (PAHs) represent an emerging class of π-conjugated molecules in the area of optoelectronic devices and materials. Unprecedented synthetic routes to various PAHs from simple phenol derivatives by a palladium-catalyzed annulative dimerization of phenylene triflate through twofold inter- and intramolecular C?H activation have been established. The initially formed partially fused PAHs can be smoothly transformed into a variety of fully fused PAHs by the Scholl reaction. Furthermore, the reactions of phenanthrene-substituted aryl triflates proceeded regioselectively. The findings inspired the development of a rapid and efficient synthesis of polybenzoacene derivatives. This study not only allows transformation of phenyl triflates, but also discloses a new retrosynthetic strategy towards PAHs, especially polybenzoacenes.
An Intramolecular Arene-Triflate Coupling Reaction for the Regiospecific Synthesis of Substituted Benzofluoranthenes
Rice, Joseph E.,Cai, Zhen-Wei
, p. 1415 - 1424 (2007/10/02)
An intramolecular triflate-arene coupling reaction mediated by bis(triphenylphosphine)palladium(II) chloride has been developed for the synthesis of each of the isomeric benzofluoranthenes.This reaction, which results in formation of a new five-membered ring, proceeds in highest yields when performed using 0.1 equiv of the palladium catalyst, 3 eqiv of lithium chloride, and 1.2 eqiv of 1,8-diazabicycloundec-7-ene in N,N-dimethylformamide at 140 deg C.The biaryl precursors needed for the coupling reaction can be prepared by nickel(II) chloride catalyzed coupling of an aryl bromide with an magnesium bromide (prepared by ortho-lithiation of an aryl methoxymethyl ether followed by transmetalation with magnesium bromide).Using this procedure benzofluoranthene, benzofluoranthene, benzofluoranthene, and benzofluoranthene were prepared in yields of 84percent, 85percent, 93percent and 64percent, respectively.The reaction to prepare benzofluoranthene was regiospecific and afforded none of the six-membered ring product, perylene.This method was extended to the preparation of benzofluoranthene (BbF) derivatives with fluoro or methoxy groups on the benzo ring.The cyclization of compounds posessing a methoxy group on the same ring as the triflate required the addition of 0.4 equiv of triphenylphosphine to the reaction mixture.Strategies are reported for the regiospecific preparation of 4-, 5-, 6-, and 7-substituted benzofluoranthenes.Evidence is presented wich suggests the intermediacy of radicals in the oxidative-addition of aryl triflates to the palladium catalyst.
A Palladium-Catalyzed Intramolecular Arene-Triflate Coupling for the Synthesis of Fluoranthrenes and Benzofluoranthrenes
Rice, Joseph E.,Cai, Zhen-Wei
, p. 1663 - 1678 (2007/10/02)
A method for the preparation of fluoranthrenes and benzofluoranthrenes from aryl bromides and aryl methoxymethyl ethers is described.The key step in this synthesis is an intramolecular triflate-arene coupling mediated by bis(triphenylphosphine)palladium(II)chloride.Fluoranthrene, benzofluoranthrene, benzofluoranthrene, and indenopyrene were prepared in yields of 84-91percent.The regiospecific synthesis of substituted benzofluoranthrenes was demonstrated by the preparation of 6-fluorobenzofluoranthrene (72percent yield) and 5- and 6-methoxybenzofluoranthrene in yields of 73percent and 62percent respectively when the reaction was conducted in the presence of excess triphenylphosphine.Key Words: synthesis; palladium; triflate; fluoranthrene; benzofluoranthrene
